Heart rate response to light in the embryo of the Japanese quail (<i>Coturnix coturnix</i>)

Abstract

Abstract The effects of exposure to light were investigated during and shortly after the period of light stimulation. A particular objective was to evaluate any responses to the type of illumination conditions generally used for observation of avian embryos. Twenty 16‐day Japanese quail embryos were illuminated for 15 minutes each during a total recording period of 55 minutes. Heart rate, respiration rate and an approximate measure of activity were recorded. Mean heart rate was found to be higher during stimulation than before and did not return to the prestimulation level during the recording period after stimulation ceased. The lack of an immediate heart rate response to the onset of stimulation separates the effects of light from those of touch, rotation, odours, tastes and maternal calls. The possibility that light may act to stimulate accelerated development is discussed.